Browsing Dissertations and Theses by Subject "Igneous rocks--Black Hills (S.D. and Wyo.)"
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Geochemical and isotopic variation of the igneous instrusives of the northern Black Hills, South Dakota (Northern Illinois University, 1986)The phonolite series of Tertiary intrusives in the Black Hills contains relatively low SiO₂ (58.6-63.7%) and high Al₂O₃ (16.67-20.79%), total iron (as FeO, 2.10-4.26%), Na₂O (6.03-9.00%), K₂O (3.60-9.59%) and LOI (1.09-4.43%). ...